There is no catalogued precedent for a metal-detector find of a gold tremissis in North Yorkshire east of York. The inscriptions and reverse monogram currently defy plausible interpretation.
A New Merovingian Tremissis – Tony Abramson
There is no catalogued precedent for a metal-detector find of a gold tremissis in North Yorkshire east of York. The inscriptions and reverse monogram currently defy plausible interpretation.
BNS Research Blog 
Do we have any accurate dating for the Merovingian coins shown in Figures 2 and 3?
Hello Peter,
Thanks for the question.
The Merovingian National Series became debased and was phased out by the 660s when silver started to be issued. Fig 3. (Melle) featured in a research paper (Loveluck et al) demonstrating this. If this doesn’t answer the question please get back to me.
BR,
T.